Air conditioning utilizing carbon



1934- H. E. MORTON 1,985,616

AIR CONDITIONING UTILIZING CARBON DIOXIDE ICE Filed July 5, I934 INVENTOR. [I '73 E. morfion BY M ATTORNEY Patented Dec. 25, 1934 UNITED STATES am CONDITIONING UTILIZING CARBON DIOXIDE ICE Harry E. Morton, Bolton, Mala, acsignor to B. I. Sturtevant Company, Inc., Boston, Mass.

Application July 5, 19:4, sfl'lll No. man 3 Claims. (01. lie-91.5)

This invention relates to the conditioning of air and relates more particularly to the use of carbon dioxide ice, commercially known as dry ice or similar sources of concentrated cold for the cooling of air for comfort purposes.

In the cooling of air for comfort purposes in passenger vehicles and in small rooms, such as those in offices, homes, and hotels, small, compact air cooling units are desired, with minimum -mechanical equipment. It has been proposed heretofore, in an attempt to dispense with mechanical refrigeration equipment, to use ordinary ice for air cooling purposes, but the weight and bulk of the ice necessary for comfort over even a short period of time has been found to be so great that the size of the air conditioning unit became too great. Furthermore, the difficulties of re-icing the units at frequent intervals was too cumbersome a task. As a result, mechanical refrigeration equipment is found in small cooling units, particularly of the portable type, despite the increased cost, noise of operation, necessity for condenser cooling facilitites, and other undesired characteristics.

According to this invention, a small, compact air cooling unit is provided for the comfort conditioning of air, using dry ice in an indirect cooling system. In one embodiment of the invention, dry ice or another suitable source of concentrated cold is used to cool condenser coils in a closed refrigeration circuit, included in which are evaporator coils used as air cooling coils, the evaporator being, in this arrangement, at a higher temperature than the condenser. The liquid in the evaporator boils freely, absorbing heat from the air passing over the coils, the gas evolved from the liquid in the evaporator being cooled by the dry ice which is in contact with the condenser coils. A thermostat exposed to the air in the space which it is desired to serve with cold air controls, through a thermo-valv the circulation of a refrigerant, and a magnetic stop valve shuts off the flow of refrigerant when the power to the fan moving the air to be cooled over the coils becomes discontinued for any reason. An auxiliary duct and a motor-driven blower associated therewith carries off the carbon dioxide released where dry ice is used, thus preventing the escape of carbon dioxide from the storage space, as when the equipment is being re-iced.

, An object of the invention is to cool the air with a minimum of equipment.

Another object of the invention isto use dry ice or other source of concentrated cold to cool airinanindirectsystem.

Another object of the invention is to use dry ice or other source of concentrated cold to cool the condenser coils in a closed refrigeration circuit in which are included evaporator coils as air cooling coils.

Another object of the invention is to use dry ice or other source of concentrated cold to cool the condenser coils in a closed refrigeration circuit in which are included evaporator coils as air cooling coils, and to provide suitable automatic controls for the successful operation of such an arrangement.

In the drawing and in the following description, the invention has been illustrated in connection with the conditioning of air in a railway passenger car, although it should be realized that the features of the invention are adapted equally as well to air cooling units for stationary purposes, particularly small, compact units which may or may not be of the portable type for the cooling of individual rooms. It is felt that the invention is suitable for'cooling railway passenger cars where it is known that the cost of supplying mechanical refrigeration to such cars is too great and the disadvantages of replenishing the ice storage bins of ice cooling systems render such systems undesirable except when very short runs are encountered.

The invention will now be described with refer ence to the drawing, of which:

Fig. 1 is a sectional, side view through an air conditioning unit according to this invention, and

Fig. 2 is a side view, with a portion of the side removed, of a railway passenger car equipped with the unit of Fig. 1.

The air conditioning unit 5 has three compartments: the compartment 6 in which are contained the cakes I of dry ice or other suitable source of concentrated cold and the condenser coils 14; the compartment 8 which contains the evaporator coils 9; and the compartment 10 which contains the fan 11, fan driving motor 12, and the recirculated air duct 13.. Each of the compartments is insulated from each other and from the external air.

The refrigeration circuit comprises the condenser coils 14 which are located above the extended surface evaporator coils 9. The condenser and evaporator coils are connected by the pipes 15 and 16, and inserted in the latter are the magnetic stop valve 17 and the thermo-valve 18, which is operated by the thermostat 19 to control'the flow of the refrigerant in the circuit in accordance with temperature changes in the space which is being supplied with cold air. The

evaporator coils normally contain a refrigerant such as methyl chloride, iso-butane, or other suitable refrigerant. Due to the fact that the condenser coils 11 are cooled by the dry ice cakes 7, the refrigerant in the evaporator coils 9 is at a higher temperature, and as the air to be cooled is blown by the fan 11 over the evaporator coils, the liquid in the evaporator boils freely and gas passes of! and into the condenser. As evaporation takes place in the evaporator, heat is absorbed from the air which is moved over them by the fan, which cooled air is discharged into the space to be served through the discharge duct 20.

The dry ice "I cools the gas in the condenser coils, condensing same back to a liquid, which drains, by gravity, back to the evaporator coils 9. The thermostat 19 controls the temperature in the space supplied by the conditioned air, under positive control, by opening and closing a solenoid-operated valve 18, which is energized from the power source 21. When no further cooling is required. the valve 18 is closed to prevent the flow of the refrigerant to the evaporator coil, with the result that the refrigerant is soon all boiled out of the evaporator, condensed in the condenser coils and the dry ice is conserved when cooling is not required.

The magnetic stop valve 17 operates when power from the source 21 is discontinued to close off the refrigerant circuit.

The recirculated air duct 13 has, mounted in its inlet 22, the filter 23, which serves to remove any undesirable impurities, such as dust and the like, from the air.

As the dry ice in the compartment 6 is consumed in cooling the condenser coils 14, carbon dioxide accumulates. The compartment 8 is provided with the insulating door 23, under which compressed cakes of dry ice may be supplied, but it is not desired to permit the accumulated carbon dioxide to be discharged into the space surrounding the unit so that the auxiliary discharge duct 24 is provided, which duct leads to the outside air through a window opening, or through a suitable opening which may be provided in a wall. Before the door 23 is opened or removed for re-icing, the auxiliary blower 25 is operated by closing the switch 26 to remove the carbon dioxide from the space 6 and to discharge it to a remote location through the discharge duct 24. The inlets to the blower 25 and duct 24 are preferably carefully insulated so that no heat is absorbed from the outside air through their intermediary.

AsshownbyFig.2,theunit5ofFig. lmaybe mounted in one end and in one diagonal corner of the railway passenger car, wherethere is ordinarily space available for such a small unit. Obviously, the same unit could'be mounted completely in the roof zone of the car by slight rearrangement of the apparatus. With the arrangement shown by Fig. 2, the distributing duct 20 is provided to one side of the unit, the door 23 for re-icing of the unit being arranged at the opposite side of the unit so that the door may be completely removed without being hampered by the duct. With the arrangement of Fig. 2, it has been determined that suilicient dry ice may be stored to enablethe apparatus to function satisfactorily during-the run between convenient re-icingstationsonahotsummerdayandon anyrailway run.

Whereas one embodiment of the invention has been described for the m ses: illustration, it should be understood that the invention is not limitedtothedetails descrlbedsincemanymodiflcations may be madeby those skilled in the art without departing from the spirit of the invention.

What is claimed is:

1. Air cooling apparatus, comprising an insulated air cooling compartment, evaporator coils arranged as air cooling coils in said compartment inthepsthoftheairtobecooledasecondim sulated compartment for the reception of solidifled carbon dioxide, condenser coils in said second compartment exposed to the cooling eifect produced therein, said evaporator and condenser coils being arranged in a closed refrigeration circuit containing a volatile refrigerant, means for moving the air to be cooled over said evaporator coils and discharging it into the space to be served, and means for removing the carbon dioxide formed in said second mentioned compartment and for discharging it to a point remote from the space to be served by said apparatus with cool air.

2. Air cooling apparatus, comprising an insulated air cooling compartment. evaporator coils arranged as air cooling coils in said compartment in the path of the air to be cooled, a second insulated compartment for the reception of a stored valve in the circuit between said condenser and evaporator coils for shutting off said circuit when the supply of power to said apparatus is disconinued.

3. Air cooling apparatus, comprising an insulated air cooling compartment, evaporator coils arranged as air cooling coils in said compartment inthepathoftheairtobecooled,asecondinsulated compartment for the reception of cakes of dry ice, condenser coils in said second compartment exposed to the cooling eifect produced therein, said evaporator and condenser coils being arranged in a closed refrigeration circuit containing a volatile refrigerant, means for moving the air to be cooled over said evaporator coils and discharging it into the space to be served, a valve in the circuit between said condenserand evaporator coils, a thermostat exposed to the temperature in the space to be served for opening and closing said valve proportional to temperature variations, a magnetic stop valve in the circuit between said condenserand evaporator coils for shutting 01! said circuit when the supply of power to said apparatus is discontinued, a duct leading from the apparatus to outside air for removing undesired carbon dioxide formed from the dry ice, a blower associated with said duct, and means for operating said blower as desired from an electric power source.

' HARRY B. HORTON. 

